Britannica learning library 015 creatures of

Albatrosses live very long lives and are one of the few species ofbirds that die of old age.. READ THESE ARTICLES… DUCKS •GULLS •PENGUINS Answer: c It goes to land only to lay eggs.. REA

Trang 1

vk com/engl i shl i brary

Trang 2

Creatures of the Waters

Encounter fascinating animals that live in and around water

LEARNING

L I B R A R Y

Trang 3

Cover photos (front): Robert Yin/Corbis; (back): Royalty-Free/Corbis Cover insert photos (left): Royalty-Free/Corbis; (center): Royalty-Free/Corbis International Standard Book Number: 978-1-59339-516-2

No part of this work may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher.

BRITANNICA LEARNING LIBRARY: CREATURES OF THE WATERS 2008

Britannica.com may be accessed on the Internet at http://www.britannica.com.

PROJECT TEAM

Judith West, Editorial Project Manager

Christopher Eaton, Editor and Educational

Consultant

Kathryn Harper, U.K Editorial Consultant

Marilyn L Barton, Senior Production

Bhavana Nair (India)

Rashi Jain (India)

Design and Media Specialists

Nancy Donohue Canfield, Design

Megan Newton-Abrams, Design

Karen Koblik, Photos

Joseph Taylor, Illustrations

Amy Ning, Illustrations

Jerry A Kraus, Illustrations

Michael Nutter, Maps

Copy Editors

Barbara Whitney

Laura R Gabler

Dennis Skord

Lisa Braucher, Data Editor

Paul Cranmer, Indexer

DESIGN

Steven N Kapusta Carol A Gaines Cate Nichols

ART

Kathy Nakamura Kristine A Strom Nadia C Venegas

ILLUSTRATION

David Alexovich Christine McCabe Thomas Spanos

MEDIA ASSET MANAGEMENT

Jeannine Deubel Kimberly L Cleary Kurt Heintz Quanah Humphreys

COPY

Sylvia Wallace Jennifer F Gierat Glenn Jenne Mary Kasprzak Thad King Larry Kowalski Joan Lackowski Dawn McHugh Julian Ronning Chrystal Schmit Sarah Waterman

INFORMATION MANAGEMENT/

INDEXING

Carmen-Maria Hetrea Edward Paul Moragne Marco Sampaolo Sheila Vasich Mansur G Abdullah Keith DeWeese Catherine Keich Stephen Seddon

EDITORIAL TECHNOLOGIES

Steven Bosco Gavin Chiu Bruce Walters Mark Wiechec

COMPOSITION TECHNOLOGY

Mel Stagner

MANUFACTURING

Dennis Flaherty Kim Gerber

INTERNATIONAL BUSINESS

Leah Mansoor Isabella Saccà

ENCYCLOPÆDIA BRITANNICA, INC.

Trang 4

InCreatures of

the Waters,

you’ll discover answers to

these questions and many

more Through pictures,

articles, and fun facts,

you’ll learn about the great

diversity of animal life

found in waters around the

world

I N T R O D U C T I O N

How did the “dabbling duck” get its name? What fish can leap up waterfalls?

Is a sponge a plant or an animal? What animals can live both in water and on land?

Creatures of the Waters

To help you on your journey, we’ve provided the following guideposts in Creatures of the Waters:

■ Subject Tabs—The colored box in the upper corner of each right-hand

page will quickly tell you the article subject

■ Search Lights—Try these mini-quizzes before and after you read the

article and see how much—and how quickly—you can learn You can even

make this a game with a reading partner (Answers are upside down at thebottom of one of the pages.)

■ Did You Know?—Check out these fun facts about the article subject.

With these surprising “factoids,” you can entertain your friends, impressyour teachers, and amaze your parents

■ Picture Captions—Read the captions that go with the photos They

provide useful information about the article subject

■ Vocabulary—New or difficult words are in bold type You’ll find

them explained in the Glossary at the end of the book

■ Learn More!—Follow these pointers to related articles in the book These

articles are listed in the Table of Contents and appear on the Subject Tabs

LEARNING

L I B R A R Y

Br itannica ®

Have a great trip!

Trang 6

Creatures of the Waters

TA B L E O F C O N T E N T S

INTRODUCTION 3

WATERBIRDS Albatrosses:Forever Gliding 6

Ducks:Dabblers, Divers, and Perchers 8

Geese:Fine-Feathered Travelers 10

Gulls:The Ocean’s Cleanup Crew 12

Penguins: Well-Dressed Swimmers 14

Swans:Birds of Beauty, Grace, and Speed 16

WATER-WISE AMPHIBIANS AND REPTILES Amphibians:The Land-and-Water Dwellers 18

Frogs:Amazing Changing Amphibians 20

Alligators and Crocodiles: Modern Dinosaurs 22

Anacondas:A Tight Squeeze 24

Turtles:Taking Their Time 26

FRESH FISH! Fish:Citizens of the Waters 28

Carp:The Fishy Survivor 30

Piranhas:Frightening Little Fish 32

Salmon:Leaping Up the Waterfall 34

Sharks:Predators of the Sea 36

MOSTLY MARINE MARVELS Coral:Builders in the Sea 38

Deep-Sea Life: Flashing Lights! 40

Jellyfish:Boneless Blobs of the Sea 42

Mollusks:Shell-Dwelling Animals 44

Octopuses:Eight-Armed Wonders 46

Sponges:Plants or Animals? 48

AQUATIC MAMMALS Buffalo:Water-Loving Beasts 50

Hippopotamuses:Kings of the River 52

Manatees:Mermaids of Yore? 54

Muskrats:The Town Builders 56

Walruses: The Whale Horses 58

Whales:The Biggest Animals of All 60

GLOSSARY 62

INDEX 63

LEARNING

L I B R A R Y

Britannica ®

Trang 7

Albatrosses use their long wings to soar and

glide on air currents They can stay in the air

for hours without flapping their wings The

black-browed albatross, shown here in flight,

Which

of the following can

be said about

an albatross? a) It spends most

of its time on land b) It eats other birds c) It goes to land only

to lay eggs.

SEA

RCH LIGH

T

Trang 8

A L B A T R O S S E S

7

The albatross is an amazing seabird It spends most of its life soaringabove the water The only time albatrosses ever go ashore is when they layeggs and raise their chicks Groups (called “colonies”) of the birds build

nests on isolated Antarctic islands Asingle large white egg is laid in abowl-shaped nest built from plants andsoil Sometimes the nest is just a patch

of bare ground

A young albatross grows slowly Ittakes at least four months for it todevelop all the feathers it will need tofly Once it’s able to fly, the albatrosswill spend the next five to ten yearsout at sea The albatross can glide forhours at a time, without flapping itslong narrow wings To stay in the air like this, it needs windy weather Incalm weather the albatross has trouble keeping its heavy body in the air, so

it rests on the water and floats like a cork It feeds on small squid and

fish But it will also follow fishing boats and eat scraps that arethrown overboard

Some kinds of albatrosses are brown, but most of them are whitewith some brown or black markings on their bodies or wings

Albatrosses are the largest of all flying birds In fact, the wanderingalbatross has the largest wingspread among living birds The wings of

a wandering albatross can measure 11 feet from tip to tip

Albatrosses live very long lives and are one of the few species ofbirds that die of old age

LEARNMORE! READ THESE ARTICLES…

DUCKS •GULLS •PENGUINS

Answer: c) It goes to land only to lay eggs. ★

In the past, sailors believed albatrosses had special powers They believed that killing the bird would bring bad luck

DID YOU KNOW?

Scientists measuring an albatross’ wingspread.

Trang 9

DID YOU KNOW?

Ducks make their feathers waterproof

by rubbing oil on them They get the oil from special glands on their chests and rub it on their feathers with their bills.

Unscramble these words that have to do with a duck wsmimre

Trang 10

D U C K S

9

Ducks are champion swimmers and are at home almost anywhere nearwater Some feed and nest in streams and ponds Others live near deepwide lakes Some make their homes on rocky cliffs by the ocean

There are three kinds of ducks:

“Dabbling ducks” put their heads underwater to eat plants that grow

there This way of feeding is called “dabbling.” They build their nests in

hollows near the water There they also eatplants and insects found near the shore

Dabbling ducks can fly very fast

“Diving ducks” dive deep down into thewater to find things to eat They mostly eat fish

They are very strong swimmers

“Perching ducks” make nests in trees andhold on to the branches with their long-clawedtoes This is called perching Some may perch onthe tall stalks that grow over marshy ponds

All ducks are graceful fliers and swimmers

But on the ground they waddle from side to side,moving slowly in a funny, jerky way You

usually don’t see a duck waddling too far awayfrom water

In winter many ducks fly south, where thewater is warmer and there’s more to eat But icycold water doesn’t bother them A thick inner layer of soft fluffy featherscalled “down” keeps them warm And their bigger outer feathers help too

They’re waterproof Feathers are a duck’s raincoat Every year ducks lose

their old feathers, and new feathers grow in This is called “molting.” Untilthe new feathers grow, ducks can’t fly So they hide in the grass or on thewater to keep safe from enemies

GEESE •GULLS •SWANS

Answer: wsmimre = swimmer nblbiadg = dabbling dlwaed = waddle

(Top) A dabbling gadwall duck;

(bottom) young girl holding a fluffy duckling.

Trang 11

Geese are found virtually everywhere There’s the wild Canada goose,and halfway around the world is the snow goose of Siberia There is the

pied goose, which lives “down under” in Australia The rarely seen

Hawaiian goose lives out in the middle of the Pacific Ocean The littlebrant goose nests in very cold Arctic areas The wild goose called thegreylag is found in Europe

Geese spend a lot of time in the water Like ducks, they have a coat ofoil on their feathers that keeps them from getting too wet And the soft

feathers beneath, called “down,” keep themwarm even in the iciest of waters Down is

so good at keeping things warm that peopleoften use it in winter coats and in

comforters It’s also good in pillowsbecause it’s so soft

Geese are fairly large birds, oftenstanding three feet tall despite their shortlegs Geese may look somewhat silly when

they waddle on land But their sturdy legs

actually help them walk more steadily thanducks or swans do

Geese have webbed feet that make themstrong swimmers They are also powerfulfliers They can make especially long

flights during their annual migrations to

their winter feeding grounds You may seegroups of geese traveling south in the fall inlines that make a V shape This formation helps keep them from gettingtired as they fly because each goose gets a lift from the air flowing off thegoose ahead

DUCKS •GULLS •SWANS

(Top) Mother goose nuzzling her gosling (young goose); (bottom) snow geese flying in a V formation.

People in Asia and Europe have kept geese as guards Geese make loud honking cries when danger appears After chasing the enemy away

, they cackle triumphantly

Trang 13

Gulls are among the most common waterbirds of ocean

and coastal zones worldwide Some gulls travel enormous

distances between their summer and winter homes.

How are gulls helpful to humans?

SEA

RCH LIGH

T

Trang 14

of insects too

Gulls eat all day long They have to just tostay alive Gulls are big birds that fly greatdistances While flying, they use up a lot ofenergy Gulls can fly many miles withoutstopping They can fly from one end of acountry to the other But all the time they’re upthere, they’re looking down to see if they can find something to eat

Gulls are good swimmers too Their feet are webbed

The little stretches of skin between their toesmake their feet act as paddles

Gulls are also floaters They stay on top of thewater like a piece of wood does On long trips overthe ocean, they drop down onto the water and floatwhile taking a nap

ALBATROSSES •DUCKS •FISH

Answer: Gulls clean up a lot of food waste from beaches, harbors, picnic areas, dumps, and parking lots that would otherwise be left behind as trash.

Seagull stands on a rock.

The type of gull called Bonaparte’

s

gull was named after Charles-Lucien Bonaparte, a nephew of the famous French emperor Napoleon Bonaparte The younger Bonaparte spent much

of his life studying the world’

Trang 15

Penguins are excellent divers and swimmers Here, gentoo penguins enjoy a romp through the water.

Do penguins have

feathers?

SEA

RCH LIGH

T

Trang 16

P E N G U I N S

15

When a penguin swims, its light-colored belly and dark-colored backhelp hide it from enemies From underneath, its light belly looks like thesky This makes it hard for its enemy the leopard seal to see it From

above, its dark back looks like the dark water,which helps hide it from big hunting birds

Penguins cannot fly, but they swimextremely well The shape of their bodies, sort

of like a submarine, lets them swim very fast

They use their short flat wings like flippers andpractically fly through the water In fact, theyoften leap out of the water and look as if theyare trying to flap through the air

There are 17 types of penguins They live inAntarctica and along the cool portions of thecoasts of Africa, New Zealand, Australia, andSouth America Penguins have a thick layer offat that helps to protect them from the cold Andalthough they don’t look like they do, they actually have feathers all overtheir bodies These short feathers also help to keep them warm

Penguins’ short legs give them an odd walk They do, however, runquickly Sometimes they’ll build up speed and then slide on their bellies totravel quickly over ice and snow

Penguins live in nesting colonies These colonies can be

enormous Penguins return to the same place, the same nest, and thesame partner every year—sometimes traveling long distances

Penguins use the Sun to help them find their direction Mostpenguins build a nest on the ground with pebbles, mud, andvegetation The females lay one or two eggs, and then both parentstake turns looking after them

ALBATROSSES •GULLS •SWANS

Answer: Like all birds, penguins have feathers But theirs are so short and close to their bodies that the feathers look more like skin.

DID YOU KNOW?

Members of the emperor penguin species, the largest of the penguins.

Trang 17

Ducks, geese, and swans are the three main kinds of waterfowl Swansare the largest of the three, and they are also the fastest flyers and

swimmers They have a stately and dignified appearance when swimming

on a pond

Like the other waterfowl, swans have oily feathers that stay dry in thewater Their webbed feet make them strong swimmers Swans are heavy-

bodied birds that feed by dabbling—

dipping the long neck into shallowwater for plants They don’t dive forfood They have powerful wings forflying long distances

The whistling swan and thetrumpeter swan are found in NorthAmerica, while the mute swan lives

in Europe and Asia These birds arewhite South America is the home ofthe black-necked swan, while the beautiful black swan lives in Australia It

is the state emblem of Western Australia

Swans make a variety of sounds Even the mute swan often hisses ormakes soft snoring sounds It may even grunt sharply

The male swan is called a “cob.” The female is called a “pen.” Theylook alike A pair of swans usually stays together for life The female swanlays about six pale eggs on a heap of plant material, while the male keepsclose guard The young swans are called “cygnets.” They can run and swimjust a few hours after they hatch But father and mother swan look afterthem carefully for several months Sometimes the cygnets

will ride on their mother’s back when they get tiredfrom swimming or need protection from enemies

LEARN MORE! READ THESE ARTICLES…

DUCKS •GEESE •GULLS

Mother swan and cygnets.

E.B White’s The Trumpet of the Swan

is a story about a voiceless swan that learns to play a trumpet.

B i rds of Be a ut y,

e d

Trang 18

S W A N S

17

Answer: Both ducks and swans are waterbirds with oily feathers and webbed feet for swimming But swans are considerably bigger than ducks They fly and swim faster than ducks too.

A family of mute swans, with cygnets riding on

their mother’s back, swim along the water.

What’s one way that ducks and

swans are alike?

How are they

Trang 19

What’s

so special about amphibians?

(Hint: Remember those Greek words.)

SEA

RCH LIGH

T

Salamanders were once believed to live in fire The word “salamander” comes from ancient words that mean

“fire lizard.”

Trang 20

The word “amphibian” comes from the Greek words amphi, which means “both,” and bios, which means “life.” As their name

suggests, amphibians live both in freshwater and on land

Amphibians are cold-blooded animals This means that anamphibian’s body temperature generally matches the temperature around

it To warm up, amphibians often bask in the sun, and to cool off, they

move into the shade Amphibians must also stay near water If their skindries out, they will die

There are three main groups of amphibians The largest groupincludes the true frogs, tree frogs, and toads True frogs have long hindlegs and can swim and leap very well Tree frogs have suction pads ontheir fingers and toes and can hold on to smooth surfaces Toads haveshorter legs than frogs, and their skin has a warty appearance

The second group of amphibians is the salamanders, which have tails

The giant salamander of Japan and China is the largest of all amphibians

It can grow to a length of more than five feet

The third group is the caecilians These odd amphibians are rarely seen

They have long slender bodies with no arms or legs They are also blind Along flexible structure called a “tentacle” sticks out next to each of theiruseless eyes They use these tentacles to feel and sniff their way around

LEARN MORE! READ THESE ARTICLES…

FISH •FROGS •TURTLES

Trang 22

F R O G S

21

Frogs are amphibians This means they canlive both in water and on land And they have alife cycle that takes place in both environments

A mother frog lays her eggs in the water In afew days tiny tadpoles, or pollywogs, wriggle out

of the eggs The tadpoles don’t look like frogs at

all They have long tails for swimming and slits called gills for breathing

As a tadpole grows into a frog, it changes in many ways Its tail gets

shorter and shorter until it disappears Atthe same time, the frog grows front andhind legs The hind feet have long toeswith webs between them to help inswimming and leaping Plus, the gills

disappear and lungs develop Once these

changes are complete, the creature is ready

to live on land as well as in the water It’snow a frog For some kinds of frogs, thisprocess of change takes just two months

For others, it may take as long as three years

A frog has smooth moist skin Its eyes are so big that they seem about

to pop out of its head These eyes help it find food Its hind legs aremore than twice as long as its front ones The frog travels in

great leaps on these long strong legs

Frogs are closely related to toads What’s the differencebetween a frog and a toad? Well, a toad’s skin is dry andbumpy Its legs are short, so it can only hop, not leap Andtoads spend more of their time on land than frogs do

AMPHIBIANS •FISH •TURTLES

Answer: daploet = tadpole sligl = gills traew = water

Red-eyed leaf frog tadpoles.

The tree frog has long legs and sticky

suckerlike disks on its feet for climbing.

The Goliath frog of W

est Africa is nearly 12 inches long!

Unscramble the following words that relate

to frogs.

daploet sligl traew

Trang 23

Today, many alligators and crocodiles are in danger of becoming extinct One reason is that many are killed each year for sport or for their skins, which are used to make purses, shoes, and belts These crocodiles are lying in the grass near Moramanga, Madagascar.

True

or false?

Alligator is another name for a crocodile.

SEA

RCH LIGH

T

Trang 24

A L L I G A T O R S A N D C R O C O D I L E S

23

If you’re looking for reptiles that have been around since the days of thedinosaurs, try alligators and crocodiles These large lizardlike animals arerelated to the giant reptiles of the past

Alligators and crocodiles are closely related They look a lot alike, but

alligators have a broad flat head with a rounded snout Most crocodiles

have a narrow, pointed snout When acrocodile closes its mouth, the fourth tooth oneach side of its lower jaw sticks out

Crocodiles are larger than alligators Theyrange from 7 to more than 20 feet long, whilemost alligators are about 6 to 8 feet long

Alligators and most crocodiles live alongthe edges of large bodies of freshwater such

as lakes, swamps, and rivers They spend a lot

of time in the water, but they can also befound on land near the water Large adults can stay underwater forover an hour without breathing

Both animals have long snouts, powerful tails, and thick skinwith bony plates underneath Their eyes, ears, and nostrils arelocated on top of their long heads Alligators and crocodiles oftenfloat with only their eyes and noses showing

Crocodiles can be found in tropical swamps and rivers in

Asia, Australia, Africa, and South America Alligators are lesswidespread The American alligator lives in the southeasternUnited States In South America there are various alligators calledcaimans The Chinese alligator lives in the Yangtze River and issmaller than the American alligator

Adult alligators and crocodiles eat mostly fish, smallmammals, and birds Sometimes they may kill deer or cattle

Crocodiles are more likely than alligators to attack humans, thoughalligators will attack if cornered

Answer: FALSE Though they are related, alligators and crocodiles are two different animals.

in northern Australia and Southeast Asia.

Australians call their crocodiles

“salties.”

DID YOU KNOW?

AMPHIBIANS •MANATEES •TURTLES

Trang 25

Find and correct the error in the following sentence:

Anacondas kill their prey with a poisonous bite.

SEA

RCH LIGH

T

Trang 26

A N A C O N D A S

25

The giant anaconda is one of the longest and heaviest snakes in theworld But this South American animal is not poisonous The anacondakills its prey by squeezing it so hard that it cannot breathe

The anaconda spends most of its time in water When an animal goes

to a river to drink, the anaconda grabs it If the prey is large, the snake

wraps itself around the animal and canchoke it The anaconda then drags thebody into the water to keep it away fromjaguars and biting ants that would be

attracted to the carcass When an

anaconda eats a large animal, it gets sostuffed that it lies still for weeks to digestits meal!

There are two types of anacondas Theyellow anaconda is the smaller of the two

It is tan or greenish yellow with large black markings across its back andblack blotches along its sides Yellow anacondas are found in the southernAmazon River area The giant anaconda is twice as big as the yellowanaconda It’s olive green with black spots The giant anaconda lives in theSouth American tropics east of the Andes Mountains and on the Caribbeanisland of Trinidad Giant anacondas can measure over 33 feet long

Despite its size, a giant anaconda is not really violent Scientists cansimply pick up an anaconda and carry it off But it may take several ofthem to lift the snake, especially if it just ate!

Answer: Anacondas kill their prey by squeezing it. ★

A T i g h t Squee z e

Giant anaconda.

A yellow anaconda lies on a log at the edge of the water Although

the anaconda spends much of its time in water, it may also crawl

on land and even climb into trees to catch birds.

Like most snakes, anacondas swallow their food whole They can open their mouths wide enough to fit around an entire goat.

ALLIGATORS ANDCROCODILES •AMPHIBIANS •SHARKS

Trang 27

Turtles are known as slow-moving animals They were around during theage of dinosaurs more than 100 million years ago Dinosaurs are gone now,but turtles are still here Slow but steady wins the race!

Like the dinosaurs, turtles are reptiles There are nearly 250 kinds ofturtles in the world today All turtles breathe air at least part of the time,

even sea turtles, which spend almost their wholelife in the ocean In addition to the ocean, turtlescan live in ponds, lakes, or rivers Other turtleslive in forests or even hot desert sands, milesaway from water Some people refer to landturtles as “tortoises.”

Turtles come in all sizes Some are no morethan 4 inches long At the other end of the scale,the Atlantic leatherback turtle may weigh asmuch as 1,500 pounds

Even sea turtles go ashore to lay their eggs

The newly hatched baby turtles arecompletely on their own They scramblefrom their nest under the sand andwalk on their tiny new flippers to the water

Land and sea turtles can take care of themselves because theycarry their houses with them wherever they go Their houses aretheir shells Some turtles can close their shells completely Thesnapping turtle can’t, but it has a powerful bite for protection

No matter where they live, turtles don’t need to hunt for food

or water all the time Some have a special place inside theirbodies where they can store water And they can store food inthe form of fat Turtles can live for days or even weeks withouthaving anything to eat or drink

AMPHIBIANS •FROGS •MOLLUSKS

Three painted turtles perched on a rock.

Fill in the blank: Land turtles are sometimes called _.

SEA

RCH LIGH

T

Trang 28

T U R T L E S

27

Answer: Land turtles are sometimes called tortoises. ★

A boy kneels to investigate a small turtle Turtles are found in lakes, ponds, salt marshes, rivers, forests, and even deserts.

Turtles can live longer than people can Turtles are known to have lived

150 years in the wild, and there are reports of turtles that were even older than that

Trang 29

Afish is a cold-blooded animal that has a backbone, lives in water,

and breathes by means of gills It normally has two pairs of fins in place

of arms and legs, as well as several other fins Most fish are covered

Size differs as much as shape Some Philippine gobies reach an adultsize of less than half an inch The whale shark, the largest of all fishes,reaches 50 feet in length and weighs about 20 tons

Fish swim mainly by sideways movements of the body and tail Thefins are used for balancing, steering, and braking To move quickly from aresting position some fish shoot a stream of water out of the gills, whichcauses them to lunge forward The fastest swimmers, such as thetuna, can travel 30 miles per hour

Most fish continue to grow as long as they live Fish that live

to an old age can become very large Carp are among this group.They may live 100 years!

CARP •SALMON •SHARKS

of t he W ater s

Fish called “mudskippers” can crawl across mudflats and wet fields in search of food Lungfish can burrow into mud when their pools dry up They lie there, for months if necessary

, until rain refills the pools.

Trang 30

Fish breathe through _.

Trang 31

DID YOU KNOW?

The common goldfish, often a child’

s first pet, is a member of the carp

family.

Trang 32

C A R P

31

The common carp is a fish that lives along the muddy bottoms ofponds, lakes, and rivers It swallows plants, insects, and anythingelse it finds to eat It was first found in Asia but was later taken intoEurope and North America Some people like to eat carp

Sometimes carp can live 100 years and grow to weigh 80 pounds

or more But not all carp grow that old or that heavy The fish that are

caught usually are under 10 years old and

do not weigh more than 10 pounds

The carp has a blunt nose and asmall thick-lipped mouth From itsupper lip dangle two pairs of feelersthat are called “barbels.”

There are three kinds of common carp

The scale carp has large scales all over itswide heavy body Its back is olive green, itssides are gold-colored, and its belly is brightyellow The mirror carp has only three or fourrows of huge scales along its sides Theleather carp is almost without scales, but ithas a very thick skin

In some ways the carp is a nuisance In

hunting for food, the carp muddies the water

This affects the life of many plants and animals A carp sometimes pushesmore valuable fish away from their food and also eats their eggs The carphas a habit of pulling out plants from their roots This keeps ducks away It

is very difficult to get rid of carp The fish can thrive even in dirty waterand can also survive in very warm and very cold water

FISH •PIRANHAS •SALMON

Answer: FALSE They live in freshwater rivers, lakes, and ponds. ★

Goldfish swimming in a bowl.

SEA

RCH LIGH

T

Colorful carp swim in a pond outside a restaurant in Japan.

In Asia and Europe carp are often raised in ponds because

it is possible to grow many fish in a small amount of water.

T he Fishy S urviv or

Trang 33

The piranha is found in the rivers and lakes of SouthAmerica It is a meat-eating fish with long, triangular, razor-sharp

teeth When hungry, the piranha can be both bold and savage.

But for such a frightening fish, it is not very big Most areabout the size of an adult’s hand

Some piranhas are silver with orange undersides

Others are almost totally black All have blunt heads andstrong jaws

In the Amazon River, there are 20 different kinds ofpiranhas The most famous is the red-bellied piranha It

has the strongest jawsand the sharpest teeth

When water levels are low, this piranhahunts in schools of more than 100 fish

Many schools join in the feast if a largeanimal has been attacked But normallyred-bellied piranhas prefer prey onlyslightly larger than themselves

Usually a group of red-bellied piranhasswim around together in search of prey

The moment the prey is found, the fish signal each other Piranhas haveexcellent hearing, so it’s possible that they signal each other with sounds

Each fish in the group has a chance to take a bite and then swim away,making way for the others

Most piranhas never kill large animals, and they almost never killhumans The smell of blood attracts piranhas, but most of them feed onwhat is left by others rather than making fresh kills For this reason theirreputation for being ferocious is not deserved

CARP •FISH •SHARKS

Why do you suppose that when water levels get low, piranhas hunt

in larger schools than they would otherwise? (Hint: How much of your body can you fit underwater in the tub once you start letting the water out?)

Định dạng
Số trang	66
Dung lượng	4,51 MB